Biology Chapter: Cellular Structure and Functions

Questions and Answers

What 3 main parts does a cell consist of?

nucleus, cytoplasm, and cell membrane

What houses the genetic material?

the nucleus

What contains the organelles?

the cytoplasm

What forms the outer boundary of the cell?

plasma (cell) membrane Signup and view all the answers

The cell membrane is and is permeable.

thin, selectively Signup and view all the answers

What regulates the movement of substances in and out of the cell, participates in signal transduction, and helps cells adhere to other cells?

plasma (cell) membrane Signup and view all the answers

What does the basic framework of the cell membrane consist of?

double layer of phospholipids, fatty acid tails (making up the interior of the membrane) Signup and view all the answers

Many types of __________________ are found in the cell membrane.

proteins (some of which are transmembrane and others that are peripheral) Signup and view all the answers

What are some of the functions of the proteins found in the cell membrane?

can function as receptors, for passage of materials across the membrane, for cellular adhesion, for cell identification, etc. Signup and view all the answers

What is the clear liquid found in the cytoplasm called?

cytosol Signup and view all the answers

What is the supportive framework in the cytoplasm called?

cytoskeleton Signup and view all the answers

What does the cytoplasm consist of?

Cytosol, cytoskeleton, and networks of membranes and organelles Signup and view all the answers

What is the endoplasmic reticulum made up of?

membranes Signup and view all the answers

What does the endoplasmic reticulum provide?

a tubular transport system inside the cell Signup and view all the answers

Why does the rough ER appear rough?

because of attached ribosomes Signup and view all the answers

What does rough ER synthesize and transport for the cell?

proteins Signup and view all the answers

Why does smooth ER appear smooth?

because it has no attached ribosomes Signup and view all the answers

What does smooth ER synthesize for the cell?

lipids Signup and view all the answers

Where are ribosomes found?

in the cytoplasm, attached to rough ER Signup and view all the answers

What are ribosomes composed of?

protein, RNA Signup and view all the answers

What do ribosomes help produce?

proteins Signup and view all the answers

What is the Golgi apparatus composed of?

flattened sacs Signup and view all the answers

What does the Golgi apparatus package?

the cell's products Signup and view all the answers

Why would a cell want to package the cell's products?

to transport materials to the outside of the cell Signup and view all the answers

What does the mitochondria contain?

enzymes needed for aerobic respiration Signup and view all the answers

The mitochondria is a major site for what?

at which food energy is captured and stored in a molecule (called ATP) Signup and view all the answers

Lysosomes contain enzymes to break down what?

cell components, bacteria, nutrient molecules, toxins, drugs Signup and view all the answers

Peroxisomes contain enzymes that function in the process of what?

synthesis of bile acids, breakdown of lipids, degradation of rare biochemicals, detoxification of alcohol Signup and view all the answers

What are microfilaments and microtubules?

thin, threadlike structures that serve as the cytoskeleton of the cell Signup and view all the answers

What are microfilaments made of?

actin (a protein) Signup and view all the answers

What do microfilaments do?

cause various cellular movements Signup and view all the answers

What are microtubules made of?

tubulin (a globular protein) Signup and view all the answers

The centrosome is made up of two hollow cylinders called what?

centrioles Signup and view all the answers

What is the purpose of the centrioles during mitosis?

to enable the correct distribution of chromosomes during cell division Signup and view all the answers

What are cilia and flagella?

motile extensions from the cell Signup and view all the answers

Which is shorter (cilia or flagella)?

cilia Signup and view all the answers

What is the cilia's function in the human body?

causes movement of substances across the surface of the cell Signup and view all the answers

What is the only flagellated cell in the body?

sperm cell Signup and view all the answers

What do vesicles form from?

part of the cell membrane Signup and view all the answers

What do vesicles carry?

liquid and solid materials into the cell Signup and view all the answers

The nucleus is bound by what?

a double-layered nuclear envelope (membrane) Signup and view all the answers

What does the nuclear envelope contain?

complex openings (called nuclear pores), that allow the passage of certain substances Signup and view all the answers

Where is the nucleolus found?

inside the nucleus Signup and view all the answers

Does the nucleolus have its own membrane?

False Signup and view all the answers

What chemicals is the nucleolus made of?

proteins and RNA (for construction of ribosomes) Signup and view all the answers

What chemicals is the chromatin made of?

DNA and protein Signup and view all the answers

What does the cell membrane control?

what substances pass through it Signup and view all the answers

What is it called when mechanisms of movement across the cell membrane are passive, requiring no energy from the cell?

passive transport Signup and view all the answers

4 examples of passive transport?

diffusion, facilitated diffusion, osmosis, filtration Signup and view all the answers

Is a cell required for passive transport to occur?

False Signup and view all the answers

What is diffusion?

movement from an area of higher concentration to an area of lower concentration to reach equilibrium Signup and view all the answers

What are some examples of substances that diffuse in the human body?

Oxygen, Carbon Dioxide, Fats (many others) Signup and view all the answers

What is the only substance that moves by osmosis?

water Signup and view all the answers

What pressure results from osmosis?

Osmotic pressure Signup and view all the answers

What process uses membrane proteins that function as carriers to move molecules (such as glucose) across the cell membrane?

facilitated diffusion Signup and view all the answers

What is a solution with the same osmotic pressure as body fluids called?

isotonic Signup and view all the answers

What is a solution with higher osmotic pressure than body fluids called?

hypertonic Signup and view all the answers

What is a solution with a lower osmotic pressure than body fluids called?

hypotonic Signup and view all the answers

Because of ____________________ pressure, molecules can be forced through membranes by the process of filtration.

hydrostatic Signup and view all the answers

What is a type of pressure (in the body) that causes filtration?

blood pressure Signup and view all the answers

Where does blood filtration occur?

blood capillaries, kidneys Signup and view all the answers

What is active transport?

moves substances from an area of lower concentration to an area of higher concentration Signup and view all the answers

Active transport requires what?

transport proteins (pumps), energy in the form of ATP Signup and view all the answers

Why would the body want to spend energy to acquire (or get rid of) something?

to get materials needed by the cell OR to eliminate waste products Signup and view all the answers

What happens in endocytosis?

molecules that are too large to be transported by other means are engulfed by an indentation of the cell membrane and carried into the cell surrounded by a vesicle Signup and view all the answers

What is exocytosis?

the reverse process of endocytosis Signup and view all the answers

What is pinocytosis?

a form of endocytosis in which cells engulf liquids Signup and view all the answers

What is phagocytosis?

a form of endocytosis in which the cell takes in larger particles (such as a white blood cell engulfing a bacterium) Signup and view all the answers

What is the cell cycle?

a series of changes a cell undergoes from when it is formed until it reproduces Signup and view all the answers

The cell cycle consists of what four major stages?

Interphase, Mitosis, Cytokinesis, Differentiation Signup and view all the answers

The cell cycle is highly regulated.

True Signup and view all the answers

Cells have a maximum number of times they can be divided because of built-in 'clocks' called ____________________ on the tips of chromosomes.

telomeres Signup and view all the answers

What are the two types of cell division?

mitosis, meiosis (produces sex cells) Signup and view all the answers

How many daughter cells are produced in mitosis?

2 (two) Signup and view all the answers

Are the daughter cells identical to the 'mother' cell?

True Signup and view all the answers

What is interphase?

a period of great metabolic activity in which the cell grows and synthesizes new molecules and organelles Signup and view all the answers

What occurs during the S phase of interphase?

the DNA of the cell is replicated in preparation for cell division Signup and view all the answers

What structure disappears during prophase?

nuclear envelope Signup and view all the answers

What appears or becomes visible during prophase?

spindle fibers, chromosomes Signup and view all the answers

Why is metaphase the easiest to see on a microscope slide?

the chromosomes line up between the centrioles in a straight line Signup and view all the answers

What events characterize anaphase?

the centromeres are pulled apart, the spindle fibers shorten, the chromatids are pulled apart Signup and view all the answers

What structure reappears during telophase?

the nuclear envelope Signup and view all the answers

What have the chromosomes done in telophase?

separated into two identical groups Signup and view all the answers

What begins during anaphase of mitosis and continues as the cell pinches into two new cells?

cytokinesis Signup and view all the answers

What is differentiation?

the process by which cells develop into different types of cells with specialized functions Signup and view all the answers

What controls differentiation?

when certain genes are turned on or off Signup and view all the answers

What is the term for the death of a cell that is a normal part of development?

apoptosis Signup and view all the answers

Study Notes

Cellular Structure

Cells consist of three main parts: nucleus, cytoplasm, and cell membrane.
The nucleus houses genetic material.
Cytoplasm contains organelles and is made of cytosol, cytoskeleton, and networks of membranes.

Cell Membrane

Forms the outer boundary of cells and is thin and selectively permeable.
Regulates movement of substances, participates in signal transduction, and aids in cell adhesion.
Composed of a double layer of phospholipids with embedded proteins.

Organelles and Their Functions

Endoplasmic reticulum (ER) provides a tubular transport system; rough ER synthesizes proteins due to attached ribosomes; smooth ER synthesizes lipids.
Ribosomes, found in the cytoplasm or attached to rough ER, are composed of protein and RNA, aiding in protein production.
The Golgi apparatus packages cell products for transport outside the cell.

Mitochondria and Energy Production

Mitochondria contain enzymes for aerobic respiration and are the main site for ATP production, capturing energy from food.

Lysosomes and Peroxisomes

Lysosomes contain enzymes for breaking down cell components, bacteria, nutrients, toxins, and drugs.
Peroxisomes contain enzymes for bile acid synthesis, lipid breakdown, and detoxification processes.

Cytoskeleton Components

Microfilaments (made of actin) and microtubules (made of tubulin) serve as the cell's supportive framework and aid in cellular movements.
Centrioles in the centrosome help in chromosome distribution during mitosis.

Cell Movement Structures

Cilia and flagella are motile extensions from cells; cilia are shorter and move substances across the cell surface, while the sperm cell is the body’s only flagellated cell.

Nucleus Structure

The nucleus is enveloped by a double-layered nuclear envelope containing nuclear pores for selective passage.
The nucleolus, within the nucleus, is involved in ribosome construction and is made of proteins and RNA.

Interactions with Substances

The cell membrane controls substance passage; mechanisms can be passive (requiring no energy) or active (requiring energy).
Types of passive transport include diffusion, facilitated diffusion, osmosis, and filtration.

Cell Transport Mechanisms

Active transport, using energy (ATP) and transport proteins, moves substances against concentration gradients.
Endocytosis engulfs large molecules, while exocytosis releases materials from the cell.

Cell Cycle and Division

The cell cycle consists of interphase, mitosis, cytokinesis, and differentiation, with specific regulatory mechanisms.
Telomeres limit cell division frequency. Mitosis produces two identical daughter cells.

Phases of Mitosis

Mitosis includes prophase (disappearance of the nuclear envelope), metaphase (chromosomes align centrally), anaphase (chromatids are pulled apart), and telophase (reformation of the nuclear envelope).

Differentiation and Cell Death

Differentiation develops specialized cells by turning genes on or off.
Apoptosis is the normal cell death process during development, which is essential for maintaining health.

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Description

Explore the intricate world of cellular structure in this quiz. Learn about the crucial parts, such as the nucleus, cytoplasm, and organelles, alongside their unique functions in maintaining cellular life. Delve into the role of the cell membrane and mitochondria in energy production and substance regulation.